1 //===- IdentifierResolver.cpp - Lexical Scope Name lookup -------*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file implements the IdentifierResolver class, which is used for lexical
11 // scoped lookup, based on declaration names.
13 //===----------------------------------------------------------------------===//
15 #include "clang/Sema/IdentifierResolver.h"
16 #include "clang/AST/Decl.h"
17 #include "clang/Basic/LangOptions.h"
18 #include "clang/Lex/ExternalPreprocessorSource.h"
19 #include "clang/Lex/Preprocessor.h"
20 #include "clang/Sema/Scope.h"
22 using namespace clang;
24 //===----------------------------------------------------------------------===//
25 // IdDeclInfoMap class
26 //===----------------------------------------------------------------------===//
28 /// IdDeclInfoMap - Associates IdDeclInfos with declaration names.
29 /// Allocates 'pools' (vectors of IdDeclInfos) to avoid allocating each
30 /// individual IdDeclInfo to heap.
31 class IdentifierResolver::IdDeclInfoMap {
32 static const unsigned int POOL_SIZE = 512;
34 /// We use our own linked-list implementation because it is sadly
35 /// impossible to add something to a pre-C++0x STL container without
36 /// a completely unnecessary copy.
37 struct IdDeclInfoPool {
38 IdDeclInfoPool(IdDeclInfoPool *Next) : Next(Next) {}
41 IdDeclInfo Pool[POOL_SIZE];
44 IdDeclInfoPool *CurPool;
45 unsigned int CurIndex;
48 IdDeclInfoMap() : CurPool(0), CurIndex(POOL_SIZE) {}
51 IdDeclInfoPool *Cur = CurPool;
52 while (IdDeclInfoPool *P = Cur) {
58 /// Returns the IdDeclInfo associated to the DeclarationName.
59 /// It creates a new IdDeclInfo if one was not created before for this id.
60 IdDeclInfo &operator[](DeclarationName Name);
64 //===----------------------------------------------------------------------===//
65 // IdDeclInfo Implementation
66 //===----------------------------------------------------------------------===//
68 /// RemoveDecl - Remove the decl from the scope chain.
69 /// The decl must already be part of the decl chain.
70 void IdentifierResolver::IdDeclInfo::RemoveDecl(NamedDecl *D) {
71 for (DeclsTy::iterator I = Decls.end(); I != Decls.begin(); --I) {
78 llvm_unreachable("Didn't find this decl on its identifier's chain!");
81 //===----------------------------------------------------------------------===//
82 // IdentifierResolver Implementation
83 //===----------------------------------------------------------------------===//
85 IdentifierResolver::IdentifierResolver(Preprocessor &PP)
86 : LangOpt(PP.getLangOpts()), PP(PP),
87 IdDeclInfos(new IdDeclInfoMap) {
90 IdentifierResolver::~IdentifierResolver() {
94 /// isDeclInScope - If 'Ctx' is a function/method, isDeclInScope returns true
95 /// if 'D' is in Scope 'S', otherwise 'S' is ignored and isDeclInScope returns
96 /// true if 'D' belongs to the given declaration context.
97 bool IdentifierResolver::isDeclInScope(Decl *D, DeclContext *Ctx, Scope *S,
98 bool ExplicitInstantiationOrSpecialization) const {
99 Ctx = Ctx->getRedeclContext();
101 if (Ctx->isFunctionOrMethod() || S->isFunctionPrototypeScope()) {
102 // Ignore the scopes associated within transparent declaration contexts.
103 while (S->getEntity() && S->getEntity()->isTransparentContext())
106 if (S->isDeclScope(D))
108 if (LangOpt.CPlusPlus) {
110 // The name declared in a catch exception-declaration is local to the
111 // handler and shall not be redeclared in the outermost block of the
114 // Names declared in the for-init-statement, and in the condition of if,
115 // while, for, and switch statements are local to the if, while, for, or
116 // switch statement (including the controlled statement), and shall not be
117 // redeclared in a subsequent condition of that statement nor in the
118 // outermost block (or, for the if statement, any of the outermost blocks)
119 // of the controlled statement.
121 assert(S->getParent() && "No TUScope?");
122 if (S->getParent()->getFlags() & Scope::ControlScope) {
124 if (S->isDeclScope(D))
127 if (S->getFlags() & Scope::FnTryCatchScope)
128 return S->getParent()->isDeclScope(D);
133 DeclContext *DCtx = D->getDeclContext()->getRedeclContext();
134 return ExplicitInstantiationOrSpecialization
135 ? Ctx->InEnclosingNamespaceSetOf(DCtx)
139 /// AddDecl - Link the decl to its shadowed decl chain.
140 void IdentifierResolver::AddDecl(NamedDecl *D) {
141 DeclarationName Name = D->getDeclName();
142 if (IdentifierInfo *II = Name.getAsIdentifierInfo())
143 updatingIdentifier(*II);
145 void *Ptr = Name.getFETokenInfo<void>();
148 Name.setFETokenInfo(D);
154 if (isDeclPtr(Ptr)) {
155 Name.setFETokenInfo(NULL);
156 IDI = &(*IdDeclInfos)[Name];
157 NamedDecl *PrevD = static_cast<NamedDecl*>(Ptr);
160 IDI = toIdDeclInfo(Ptr);
165 void IdentifierResolver::InsertDeclAfter(iterator Pos, NamedDecl *D) {
166 DeclarationName Name = D->getDeclName();
167 if (IdentifierInfo *II = Name.getAsIdentifierInfo())
168 updatingIdentifier(*II);
170 void *Ptr = Name.getFETokenInfo<void>();
177 if (isDeclPtr(Ptr)) {
178 // We only have a single declaration: insert before or after it,
180 if (Pos == iterator()) {
181 // Add the new declaration before the existing declaration.
182 NamedDecl *PrevD = static_cast<NamedDecl*>(Ptr);
187 // Add new declaration after the existing declaration.
194 // General case: insert the declaration at the appropriate point in the
195 // list, which already has at least two elements.
196 IdDeclInfo *IDI = toIdDeclInfo(Ptr);
197 if (Pos.isIterator()) {
198 IDI->InsertDecl(Pos.getIterator() + 1, D);
200 IDI->InsertDecl(IDI->decls_begin(), D);
203 /// RemoveDecl - Unlink the decl from its shadowed decl chain.
204 /// The decl must already be part of the decl chain.
205 void IdentifierResolver::RemoveDecl(NamedDecl *D) {
206 assert(D && "null param passed");
207 DeclarationName Name = D->getDeclName();
208 if (IdentifierInfo *II = Name.getAsIdentifierInfo())
209 updatingIdentifier(*II);
211 void *Ptr = Name.getFETokenInfo<void>();
213 assert(Ptr && "Didn't find this decl on its identifier's chain!");
215 if (isDeclPtr(Ptr)) {
216 assert(D == Ptr && "Didn't find this decl on its identifier's chain!");
217 Name.setFETokenInfo(NULL);
221 return toIdDeclInfo(Ptr)->RemoveDecl(D);
224 /// begin - Returns an iterator for decls with name 'Name'.
225 IdentifierResolver::iterator
226 IdentifierResolver::begin(DeclarationName Name) {
227 if (IdentifierInfo *II = Name.getAsIdentifierInfo())
228 readingIdentifier(*II);
230 void *Ptr = Name.getFETokenInfo<void>();
231 if (!Ptr) return end();
234 return iterator(static_cast<NamedDecl*>(Ptr));
236 IdDeclInfo *IDI = toIdDeclInfo(Ptr);
238 IdDeclInfo::DeclsTy::iterator I = IDI->decls_end();
239 if (I != IDI->decls_begin())
240 return iterator(I-1);
253 /// \brief Compare two declarations to see whether they are different or,
254 /// if they are the same, whether the new declaration should replace the
255 /// existing declaration.
256 static DeclMatchKind compareDeclarations(NamedDecl *Existing, NamedDecl *New) {
257 // If the declarations are identical, ignore the new one.
261 // If the declarations have different kinds, they're obviously different.
262 if (Existing->getKind() != New->getKind())
263 return DMK_Different;
265 // If the declarations are redeclarations of each other, keep the newest one.
266 if (Existing->getCanonicalDecl() == New->getCanonicalDecl()) {
267 // If either of these is the most recent declaration, use it.
268 Decl *MostRecent = Existing->getMostRecentDecl();
269 if (Existing == MostRecent)
272 if (New == MostRecent)
275 // If the existing declaration is somewhere in the previous declaration
276 // chain of the new declaration, then prefer the new declaration.
277 for (Decl::redecl_iterator RD = New->redecls_begin(),
278 RDEnd = New->redecls_end();
283 if (RD->isCanonicalDecl())
290 return DMK_Different;
293 bool IdentifierResolver::tryAddTopLevelDecl(NamedDecl *D, DeclarationName Name){
294 if (IdentifierInfo *II = Name.getAsIdentifierInfo())
295 readingIdentifier(*II);
297 void *Ptr = Name.getFETokenInfo<void>();
300 Name.setFETokenInfo(D);
306 if (isDeclPtr(Ptr)) {
307 NamedDecl *PrevD = static_cast<NamedDecl*>(Ptr);
309 switch (compareDeclarations(PrevD, D)) {
317 Name.setFETokenInfo(D);
321 Name.setFETokenInfo(NULL);
322 IDI = &(*IdDeclInfos)[Name];
324 // If the existing declaration is not visible in translation unit scope,
325 // then add the new top-level declaration first.
326 if (!PrevD->getDeclContext()->getRedeclContext()->isTranslationUnit()) {
336 IDI = toIdDeclInfo(Ptr);
338 // See whether this declaration is identical to any existing declarations.
339 // If not, find the right place to insert it.
340 for (IdDeclInfo::DeclsTy::iterator I = IDI->decls_begin(),
341 IEnd = IDI->decls_end();
344 switch (compareDeclarations(*I, D)) {
356 if (!(*I)->getDeclContext()->getRedeclContext()->isTranslationUnit()) {
357 // We've found a declaration that is not visible from the translation
358 // unit (it's in an inner scope). Insert our declaration here.
359 IDI->InsertDecl(I, D);
364 // Add the declaration to the end.
369 void IdentifierResolver::readingIdentifier(IdentifierInfo &II) {
370 if (II.isOutOfDate())
371 PP.getExternalSource()->updateOutOfDateIdentifier(II);
374 void IdentifierResolver::updatingIdentifier(IdentifierInfo &II) {
375 if (II.isOutOfDate())
376 PP.getExternalSource()->updateOutOfDateIdentifier(II);
379 II.setChangedSinceDeserialization();
382 //===----------------------------------------------------------------------===//
383 // IdDeclInfoMap Implementation
384 //===----------------------------------------------------------------------===//
386 /// Returns the IdDeclInfo associated to the DeclarationName.
387 /// It creates a new IdDeclInfo if one was not created before for this id.
388 IdentifierResolver::IdDeclInfo &
389 IdentifierResolver::IdDeclInfoMap::operator[](DeclarationName Name) {
390 void *Ptr = Name.getFETokenInfo<void>();
392 if (Ptr) return *toIdDeclInfo(Ptr);
394 if (CurIndex == POOL_SIZE) {
395 CurPool = new IdDeclInfoPool(CurPool);
398 IdDeclInfo *IDI = &CurPool->Pool[CurIndex];
399 Name.setFETokenInfo(reinterpret_cast<void*>(
400 reinterpret_cast<uintptr_t>(IDI) | 0x1)
406 void IdentifierResolver::iterator::incrementSlowCase() {
407 NamedDecl *D = **this;
408 void *InfoPtr = D->getDeclName().getFETokenInfo<void>();
409 assert(!isDeclPtr(InfoPtr) && "Decl with wrong id ?");
410 IdDeclInfo *Info = toIdDeclInfo(InfoPtr);
412 BaseIter I = getIterator();
413 if (I != Info->decls_begin())
414 *this = iterator(I-1);
415 else // No more decls.